Apparatus for direct contact condensation of vapors



Dec. 6, 1966 K. D. BROWN 3,290,229

APPARATUS FOR DIRECT CONTACT CONDENSATION OF VAPORS Original F iled Jan.25, 1962 6 Sheets-Sheet 1 INVENTOR. Kenard D. Brown ATTORNEYS.

Dec. 6, 1966 K D. BROWN 3,290,229

APPARATUS FOR DIRECT CONTACT CONDENSATION OF VAPORS Original Filed Jan.25, 1962 6 SheetsSheet 2 INVENTOR. Kenard D. Brown ATTORNEYS Dec. 6,1966 K. D. BROWN 3,290,229

APPARATUS FOR DIRECT CONTACT CONDENSATION OF VAPORS Original Filed Jan.25, 1962 e Sheets-Sheet :s

INVENTOR.

Kenard D. Brown MiW ATTORNEYS K. D. BROWN Dec. 6, 1966 APPARATUS FORDIRECT CONTACT CONDENSATION OF VAPORS 6 Sheets-Sheet 4 Original FiledJan. 25, 1962 IN VEN TOR.

Kenard D. Brown BY ATTORNEYS Dec. 6, 1966 K. D. BROWN 3,290,229

APPARATUS FOR DIRECT CONTACT CONDENSATION OF VAPORS Original Filed Jan.25, 1962 6 Sheets-Sheet 5 INVENTOR. Kena rd 0. Brown MKQQM ATTORNEYSDec. 6, 1966 K. D. BROWN 3,290, 9

APPARATUS FOR DIRECT CONTACT CONDENSATION 0F VAPORS Original Filed Jan.25, 1962 6 Sheets-Sheet 6 INVENTOR. Kenard D. Brown ATTORNEYS UnitedStates Patent 3,290,229 APPARATUS FOR DIRECT CONTACT CONDENSATION 0FVAPORS Kenard D. Brown, 1227 S. Willow St., Casper, Wyo. Originalapplication Jan. 25, 1962, Ser. No. 168,675, now

Patent No. 3,204,861, dated Sept. 7,1965. Divided and this applicationDec. 14, 1964, Ser. No. 418,112

11 Claims. (Cl. 202-177) This application is a division of my copendingapplication Serial No. 168.675, filed January 25, 1962.

This invention relates to vacuum pumps and to systems employing suchpumps and particularly to an improved pump and control system forpumping large volumes of gas and for facilitating the purification ofliquid and the like.

Many industrial processes require large volumes of gas to be pumpedcontinuously and various types of pumps and blowers have been proposedor employed for this purpose. Certain of these applications require thatrelatively low pressures he maintained and conventional expansiblechamber, displacement and centrifugal pumps have not proved entirelysatisfactory for these applications. By way of example, it has beenproposed to maintain relatively low pressures in oil wells to facilitatethe production of oil but conventional equipment has proved to beuneconomical and difficult to maintain in operation for this purpose.Another application of vacuum pumps occurs in the separation of waterand material dissolved or suspended therein. Here it has been founddifficult to maintain the required low pressures while removing largevolumes of water vapor.

It is an object of this invention to provide an improved apparatus formaintaining low pressures in oil wells and the like and for facilitatingthe production of volatile constituents therefrom.

It i another object of this invention to provide an improved apparatusfor effecting the evaporative separation of water and solids mixed ordissolved therein.

It is a further object of this invention to provide an improvedevaporation and condensing apparatus for purifying liquids.

It is a still further object of this invention to provide an improvedapparatus for effecting the evaporative purification of water on a largescale.

Briefly, in carrying out the object of this invention in one embodimentthereof, a vacuum pump is provided which comprises a tank containing abody of liquid-in which is immersed a pump having a rotor of the screwor helical type arranged in a cylinder or shroud closed at one end andopening into the tank at the other. The pump is provided with a gasinlet and a liquid inlet adjacent its closed end, the liquid inlet beingarranged to admit liquid from the tank. The pump during operationproduces a vortex in the shroud and the vortex is controlled byadjusting the liquid inlet opening. It has been found that by properadjustment of the rate of'recirculation of the liquid a highly effectivepumping action is secured which is capable of maintaining a high vacuum(low gas intake pressure) when the liquid intake supply is regulated andwill pump a high volume of gas. The pump operates effectively as avacuum pump and will maintain a vacuum in an oil well where it maintainsa continuous and steady pressure and greatly facilitates the productionof oil and of volatile constituents. In another embodiment of theinvention the pump is employed in combination with an evaporativepurifying system for water and provides an efficient evaporative systemfor desalting sea water.

The features of novelty which characterize this invention are set forthin the claims annexed to and form- 3,290,229 Patented Dec. 6, 1966 ICCing a part of this specification. The invention itself, however, both asto its organization and method of operation will be better understoodupon reference to the following description taken in connection with theaccompanying drawings, in which:

FIG. 1 is an elevation view partly in section to show the interiorillustrating a vacuum pump used in systems embodying the invention;

FIG. 2 is an enlarged sectional view of the shroud and rotor of the pumpof FIG. 1;

FIG. 3 is a somewhat diagrammatic view partly in section illustrating anoil well heating system embodying the invention;

FIG. 4 is a view similar to that of FIG. 2 illustrating a waterpurifying system embodying the invention;

FIG. 5 is another view similar to FIG. 3 illustrating a water desaltingsystem embodying the invention;

FIG. 6 is an elevation view partly in section illustrating a boatprovided with a sea water desalting system embodying the invention; and

FIG. 7 is a sectional view taken along the line 7-7 of FIG. 6.

Referring now to the drawings, the vacuum pump shown in FIG. 1 includesa generally cylindrical closed tank 10 having its walls insulated asindicated at 11 and mounted on a supporting base 12. The tank isarranged to be filled with a liquid such as water to a predeterminedlevel indicated at 13 and with a condensed petroleum liq id to a level13a maintained by operation of a float valve 14 in a manner to bedescribed below. In the lower portion of the tank and mounted on theleft-hand wall as shown there is provided a pump 15 comprising acylindrical sleeve or shroud 16 and a screw or helical rotor 17 mountedon a horizontal shaft 18 for rotation partly within the shroud. Thediameter of the rotor is enough smaller than the internal diameter ofthe sleeve 16 to leave a substantial annular clearance space. The leftend of the shroud adjacent the tank wall is closed while the right endopens into the tank. The rotor 17 extends a short distance into theshroud, the major portion of the screw lying outside the shroud.

Liquid is circulated from the tank through the pump 15 under control ofa valve 20 for varying the water admitted to the shroud through an inlet21 in the bottom wall thereof. Gas or vapor from a supply line 22, whichmay, for example, be connected to an oil well (not shown) is admitted tothe pump through a vapor inlet 23 in the top wall thereof. Both theliquid inlet 21 and the gas inlet 23 communicate with the pump 15 withina chamber 24 formed between the closed end of the shroud and the rotor17. The shaft is journaled in bearings 25 and 26 and is driven by asuitable prime mover illustrated as an internal combustion engine 27.When the rotor 17 is driven at a suitable speed, say 900 revolutions perminute, gas is drawn into the pump through the inlet 23 and a vortexforms about the shaft 18 decreasing in diameter toward the right asindicated by dotted lines in FIG. 2. The water or other liquid is forcedoutwardly by centrifugal force and forms an effective seal around therotor. Condensible vapors are liquefied in'the .vortex and in the waterin the tank, noncondensibles being released into and rising throughthemain body of liquid in the tank. In order to secure effective andefiicient operation of the pump it is necessary to adjust the liquidreturn through the inlet port the optimum valve setting has beenattained, large volumes of gas are drawn into the pump and condensed.

The pump at this setting is capable of maintaining a relatively highvacuum While pumping large volumes of gas.

The rapid condensation of vapor by operation of the rotor 17 raises thelevel 13a of the petroleum liquid in the tank and a float 30 whichoperates the valve 14 rises and opens the valve to discharge liquiduntil the level is restored. The discharged liquid is supplied to aproduction line or pipe 29 for use or transportation.

When the pump is operated to pump a petroleum gas well, for example, theheavier hydrocarbons are condensed in the liquid in the tank while thelighter hydrocarbons, non-condensible under the conditions of operationof the pump, are collected in the tank above the level of liquidtherein. These gases rise into a dome 31 and are removed through pipes32 and 33 or through a suitable pop off valve 31a. The pipe 32 may beemployed to supply gas to the engine 27 to supplement or replace theusual fuel supply through a supply line 34. The line 33 is employed tosupply cooling gas to the pump; this gas passes through a heat transferunit 35, cooled by air or other suitable fluid, and is then returned tothe pump through a heat exchanger 36 in the liquid in the lower portionof the tank and thence through a nozzle 37 into the chamber 24. Theoperation of this heat transfer arrangement may be controlled by a valve40 actuated automatically in response to the temperature of the liquidin the tank as determined by a temperature sensing element 41 locatedtherein.

In this application of the vacuum pump it is desirable to maintain arelatively low temperature of the water in the tank and it is for thisreason that the rotor 17 is confined only at the entrance of the shroud.As will be pointed out below, the enclosure of a substantial length ofthe rotor in the shroud results in the generation of a very substantialquantity of heat which is desirable for many applications of theinvention. The cooler temperatures realized in the pump of FIG. 1facilitate the condensation of the heavier hydrocarbons and the returnof cooled gas through the line 33 further effects cooling of the liquid.

The diameter of the rotor determines the size of the vortex formedduring the operation of the pump. For a given shaft speed the larger thediameter of rotor the larger the vortexand the greater the peripheralspeed of of the turns of the helix. The volumetric capacity of the pumpis determined by the speed of the shaft and the length of pitch of thehelix. It will thus be apparent that a wide range of design isavailable. The spacing of the rotor from the shroud or cylinder wall mayalso be varied within a relatively wide range dependent upon theapplication for which the pump is intended. In all cases the control ofthe admission of liquid to the pump cylinder is relatively critical andis adjusted to effect the optimum performance in each application andcondition of operation.

For many applications of the pump of this invention it is desired togenerate substantial quantities of heat, and FIG. 3 illustrates a systemwherein such heat is employed to facilitate the production of relativelyviscous petroleum. In this embodiment a pump assembly indicatedgenerally at 45 and which is similar to that shown in FIG. 1 isconnected by a vacuum or suction line 46 to remove gas from a wellcasing 47, the suction line being connected in communication with theinterior of the casing through a well head fitting 48. Liquid petroleumis removed from the well by operation of a pump 50 connected by a suckerrod 50a to be driven by a horsehead 50b; the pump receives liquid fromthe formation and delivers it to a production stream or tube 51.

In order to heat the well fluids in the well, high temperature liquid issupplied from the tank 52 of the pump assembly 45 through a line 53under control of an automatic valve 54 having a temperature sensingelement 55 immersed in the liquid in the tank. The line 53 extendsdownwardly into the well between the casing and the tubing 51 so thatthe hot liquid flows downwardly alongside the production tube and heatsthe liquid petroleum flowing upwardly therethrough; the hot liquid thusflows down into the well and over the producing surface of the formationwhere it counteracts the refrigerating effect of the liquid vaporizedunder the low pressure; the liquid then flows upwardly with the wellfluids through the tube 51. The vacuum pipe 46 maintains the well at lowpressure during the operation of the pump 45 and greatly facilitates theproduction of the well fluids. The pump 45 maintains a steady suctionline pressure and has been found very effective in increasing the rateof production from petroleum formations which have been relatively lowrate producers.

The pump assembly 45 includes a pump 56 comprising a sleeve or shroud 57and a helical rotor 58 mounted on a shaft 60 for rotation in the shroudby operation of an internal combustion engine 61. The shaft 60 isjournaled in bearings 62 and 63 and the rotor 58 is positioned withinthe sleeve 57 substantially throughout its length, the rotor diameterbeing smaller than the internal diameter of the sleeve and providing anappreciable spacing therebetween. The shroud is closed at its righthandend by a plate 64 and a suction chamber 65 is formed between the endplate and the rotor 58. This arrangement which provides a longer portionof the rotor in the shroud results in the generation of larger amountsof heat in the liquid which is thereby maintained by higher temperaturesthan in the embodiment of FIG. 1.

Liquid is admitted to the pump under control of a valve 66 whichcontrols a passage from valve inlet 67 in the tank to a pump intake port68. The valve has been illustrated as manually controlled by a handwheel 70. Gas or vapor from the well flows through the suction line 46to a vapor inlet or port 71 entering the chamber 65. It will be notedthat both intake ports 68 and 71 enter the chamber 65 behind the lastturn or blade of the rot-or 58; this arrangement of the rotor and portsassures effective operation of the pump.

The bearing 63 adjacent the suction side of the pump is sealed by liquidcirculated from the tank through a compartment 72 in the bearingassembly and thence to the pump intake. For this purpose liquid is drawnfrom an outlet 73 in the side of the tank through a pipe 74 to thecompartment 72 and thence to the chamber 65 under control of a valve75:: through a conduit 75 open ing adjacent the inlet of the valve 66.This prevents leakage of air into the suction side of the pump throughthe bearing 63.

In this application the liquid in the tank 52 is petroleum and otherwell fluids and is maintained at a level 76 by operation of a floatvalve 77 actuated by a float 78; when ever the liquid level fallssufficiently the float opens the valve and admits petroleum from theproduction line indicated at 51a through a connection 80.

Volatile petroleum components collect above the level of the liquid inthe tank and fill a dome 81; these gases are removed from the domethrough a line 82 and are supplied as fuel for the engine 61, excessgases being removed by a pop off valve 81a. Fuel gas may also besupplied through a second source indicated as a supply line 83.

Additional heat may be supplied to the liquid in the tank 52 from thehot exhaust gases of the engine or from its cylinder jacket coolingsystem; by way of example, a heat exchange device 84 has been shownimmersed in the liquid in the tank and connected to receive the hotfluid from the engine 61 and to return the fluid to the engine after ithas been cooled by this heat exchanger.

The valve 54 is controlled to open and admit hot liquid tothe wellcasing when the temperature as sensed by the element 55 is above apredetermined value. The system thus operates to maintain a low pressurein the well formation and simultaneously supply hot well fluid or otherliquid to heat the viscous petroleum fluids and facilitate theirproduction from the formation and their flow through the productionpipes under operation of the pump 50.

The system of this invention including the vacuum pump may be employedeffectively for purifying liquids such as muddy river water and sewageand a system for this purpose is diagrammatically illustrated in FIG. 4.The vacuum pump is essentially the same as that disclosed in connectionwith FIG. 3 and comprises an insulated closed tank 86 within whichliquid is maintained to a level indicated at 87 and having a rotary pumpassembly 88 submerged in the body of liquid for drawing gas or vaporthrough a suction line 89. The pump includes a cylindrical sleeve orshroud 91 and a helical rotor 92 mounted on a shaft 93 driven by aninternal combustion engine 94. The shaft is mounted in bearings 95 and96 in essentially the same manner as the shaft of FIG. 3.

The sleeve 91 is closed at its left-hand end as illustrated whichprovides an intake chamber 97 between the left end of the rotor and thewall of the tank. The suction line 89 opens into the chamber 97 at aport 98 to the rear of the rotor 92 and liquid from the tank is admittedto the sleeve through an intake port 99 under control of a valve 101provided with a hand wheel 102 similar to that employed in theembodiments previously described. The rotor 92 has a diametersubstantially less than that of the sleeve 91 and operates in the samemanner as the rotor 58 of the embodiment of FIG. 3 to produce a vortexabout the rotor resulting in a high vacuum together with the generationof heat within the liquid in the tank and condensation of, vaporspassing therethrough.

The bearing 95 is provided with a liquid seal similar to that of thebearing 63 in FIG. 3, liquid being circulated from the body of liquid inthe tank 86 through a line 103 to a sealed chamber 104 and thence to theinlet of the valve 101 through a connection 105 controlled by a handvalve 106. This sealing arrangement prevents the admission of air to theinlet chamber of the pump through the bearing assembly.

Liquid to be treated, which may for example be river water or sewage, isadmitted to the system from a supply through a connection 107 and passesthrough a pipe 108 to an upright tower 109 which it enters at a nozzle111 under control of a float valve 111a, the nozzle being positionedabove the surface of liquid in the tower indicated at 112. The tower 109is of sufiicient height to prevent withdrawal of liquid by the suctionpressure in the line 89 which is connected in communication with thetank through a head fixture 113.

Heat is supplied to the liquid within the tower 109 through a heatexchanger 114 connected to receive heat transfer liquid through line 115from jacket 117 of the engine 94 and to return the liquid through line116. In addition, liquid is withdrawn from the tower 109 by operation ofa pump 118 which discharges the liquid through a pipe 119 to a heatexchanger 121 and returns it to the tower 109 through a pipe 122. Theliquid to be treated which is supplied from the line 107 may also beheated as it passes through a heat exchanger 127 which receives freshwater or other purified liquid from a collecting tank 128. Thecollecting tank is connected to receive hot fresh water from the tank asthrough a line 129 and to supply liquid to the heat exchanger 127through a connection 131 and thence to the pump inlet 98 through a line132. The admission of water from the line 132 to the pump chamber 97 iscontrolled by a hand valve 124. The water cooled by heat exchange withthe incoming water in the line 107 is substantially cooler than thewater in the tank 86 and facilitates the production of lower pressuresat the pump inlet. The production of lower pressures is furtherfacilitated by insulating the pump shroud or casing 91 as indicated at125 thereby further reducing the rise of temperature of the water in theshroud.

It will thus be apparent that the liquid to be treated which is suppliedto the tower 109 after being heated and on being discharged into thetower a substantial portion of this liquid will flash into vapor and 'bewithdrawn through the line 89 by operation of the pump, the vaporthereby being separated from the foreign matter carried into the tower.The concentrated liquid then falls to the body of liquid within thetower and further portions are further evaporated from the surface 112,the concentrated foreign matter collecting in the bottom portion of thetower as indicated at 133. After a substantial accumulation of theforeign matter 133, the system is stopped, whereupon the accumulatedmatter may be removed by a helical screw 134 driven by an electric motor135 and thereby discharged through a valved plate structure 136 which isopen to allow the material to be driven therethrough when it is to beremoved from the tower.

In order to assure a minimum passage of liquid particles through theline 89, a separator or scrubber 137 may be provided. This scrubber mayinclude heating apparatus (not shown) to vaporize any such particles andremove any substances carried thereby. It will be understood that theprovision of the unit 137 will not be necessary in many installationsand is merely a refinement to assure removal of the last vestige offoreign matter from the vapor stream.

The vapor removed from the liquid within the tower 109 is thus suppliedto the-pump 88 and is condensed by operation of the pump and added tothe liquid within the tank, which then rises above the level 87 andflows into the auxiliary tank 128, from which it is removed through apure water supply line 138. The tank 128 is preferably open to theatmosphere through a connection 139. The tank 86 is also open to theatmosphere through a connection 140.

A further temperature control is provided for the liquid flowing fromthe line 107 to the supply line 108 and comprises a heat exchange coil141 arranged in the tank 128 in heat exchange with the purified watertherein together with a normally closed valve 142 and a normally openvalve 143. The valves 142 and 143 are controlled in accordance with thetemperature of the water within the tank 86 as determined by a sensingelement 144; when the temperature falls below a predetermined value, thevalve 143 is closed and the valve 142 opened so that the water from theline 107 is circulated through the tank 128- and picks up heat from thewater therein.

During the operation of the system illustrated in FIG. 4, large volumesof vapor are removed from the tower 109 and condensed and the systemprovides a highly efiicient and rugged arrangement for purifying watercontaining solids. It will be understood that the operation of the pump88 produces very substantial amounts of heat and relatively hightemperatures of the water contained in the tank 86.

The system of this invention may also be employed for the purificationof water containing foreign matter in solution and, for example, may beused for desalting brackish water or sea water to produce pure water fordomestic use or the like. A system for this purpose is illustrated inFIG. 5. In this system a vacuum pump of the closed tank type similar tothat described in connection with the previous embodiments is employed.As illustrated, the vacuum pump of this system comprises a closed tank146 having a rotary pump 147 mounted therein below the normal level ofliquid indicated at 148. The pump 147 is driven by an internalcombustion engine 149 having a shaft 151 mounted in bearings 152 and 153and on which the helical rotor indicated at 154 is mounted. The rotor154 rotates within a housing or shroud 155 which has an internaldiameter sub- 7 st antially greater than that of the rotor and providesan inlet chamber 156 between the left-hand end of the housing and theleft-hand end of the casing as shown.

During the operation of the system fresh or purified water collects inthe tank 146 and is discharged through an overflow or outlet 146a, thetank being at atmospheric pressure as indicated by an outlet pipe 157.The overflowing fresh water collects in an accumulator or auxiliary tank158 and is discharged therefrom for use through an overflow connection160.

The pump system as just described is connected to evaporate water froman evaporating chamber comprising an upright tower 161 the outlet ofwhich is connected to a closed header 162 as indicated at 163 andconducts the vaporized water through a steam separator 164 and outletconduit 165 to an inlet or suction connection 166 of the pump 147. Thesuction line 166 is connected to the pump 147 in communication with thechamber 156 as in the arrangements of the pumps previously described.

Salt water to be purified is admitted to the system through a supplyline 167 and normally flows through conduits 168 and 169 throughparallel heat exchangers 170 and 171 to a line 172 connected to supplysalt water to the towed 161. The inlet line 172 terminates in a nozzleor head 173 within the tower 161 and delivers the liquid into the zoneabove the normal liquid level in the tower at 174. The nozzle 173 spraysthe salt water into the tower where a portion of it is flashedimmediately into vapor, the remainder falling to the body of liquid atthe bottom of the tower; the tower is heated by a heat exchanger 175connected in the liquid cooling system of the internal combustion engine149 by lines 176 and 177; this cooling system is similar to that of FIG.4 and circulates a suitable liquid heated by the engine block or exhaustgases or both. The tower 161 is maintained under a vacuum or lowpressure by operation of the pump 147 and the withdrawn water vaporadmitted to the pump is condensed by operation of the pump and added tothe water within the tank 146. Any air or other non-condensible gasespassing through the system may be removed through the outlet 157.

The tower 161 is made sufficiently tall that the suction pressurecreated by the pump 147 cannot draw liquid from the body of liquidwithin the tower into the exhaust line 163. The height to which watercan be raised by operation of a vacuum is dependent upon the atmosphericpressure since it is the difference between atmospheric pressure andpressure in the pump which determines the pressure difference tending toforce the liquid water upwardly through the tower 161. It is necessaryto remove the concentrated solution or salt water from the tank and forthis purpose an inverted-U or siphon 178 is provided which is connectedto the bottom of the tower 161 at 180 and to a discharge line at itsother end as indicated at 181. The height of the inverted-U 178 is madesuflicient to prevent the drawing of air into the system from the loopduring operation of the pump at its lowest suction pressure, the siphonprovides the overflow for excess liquid within the body in the tower 161and thus maintains the normal level 174 of the liquid in the tower. Theloop 178 thus provides an overflow for the tank While at the same timepreventing the breaking of the vacuum pressure within the tower 161. Thesteam separator 164 is provided in the line 163 in order to retainparticles of water which may reach the line 163 and allow them toevaporate before proceeding into the suction line 165.

During the operation of the system, should the temperature of the waterwithin the tank 146 fall below a preselected value, a temperaturesensing element 182 will cause operation of a pair of valves 183 and 184to close the direct communication between the inlet 167 and the lines168 and 169 and to open communication between the line 167 and a heattransfer coil 185 within the tank 158. Upon this change in the circuitsthe salt water to be treated 8 passes through the coil 185 in the tank158 and is heated by the water in this tank before proceeding throughthe heat exchangers 170 and 171 in the tank 146.

The system as illustrated also includes the sealing chamber for thebearing 153 as indicated at 190, this chamber being filled with watercirculated from the tank 146 by operation of a supply line 191 connectedto the lower portion of the tank 146 and conducting the liquid throughthe chamber to a connection 192 under control of a hand valve 193. Thiscirculated water is supplied'to the intake side of a valve 193 whichcontrols the recirculation of water from the tank 146 through the pump147 in the same manner as the liquid intakes of the pumps describedabove.

During operation of the system the valve 194 is adjusted by a handcontrol indicated as a wheel 193 so that optimum conditions arerealized. Under these conditions of operation low pressure is achievedin the suction line 166 and large amounts of heat are liberated into thewater within the tank 146. This heat is available to heat the supplywater and facilitate the flashing of the salt water into steam withinthe tower 161. Under optimum conditions the vortex formed by the helicalrotor 154 acts eifectively to withdraw and condense the steam passingthrough the inlet conduit 166, the steam not condensed within the shroudbeing condensed shortly after emerging from the shroud at the right endof the pump.

The system as illustrated in FIG. 5 makes it possible to provideeffective pumping and evaporation of water from sea water and the likewithout requiring that moving parts of the system be located in the saltwater and subject to the heavy corrosion resulting therefrom. In thepresent installation it will be noted that the pump and its bearings areall located where they are subject only to wetting by the fresh waterproduced by operation of the system.

The system of this invention may also be employed for installation on aship or other vessel such as a barge anchored offshore, and in FIGS. 6and 7 a system of this type is illustrated As shown in these figures afloating barge or other vessel 200 is provided with a cylindricalinsulated tank 201 mounted to extend a substantial distance into thewater below the vessel. In the lower portions of the tank there isarranged a pump 202 of the same general construction as the pumpspreviously described and which comprises a cylindrical sleeve or shroud203 within which is mounted a helical rotor 204 driven by an electricmotor 205 by rotation of a shaft 206 mounted in suitable hearings in theWalls of the tank structure. In the arrangement illustrated the motor205 is located in an offset portion or housing formed at one side of thetank.

Access to the compartment in which the motor 205 is located may be hadthrough a door 207 hinged at the bottom end of a vertical passage 208within the tank and which is closed at the top by a plate 209 bolted tothe top cover of the tank. The tank 201 is arranged to hold a body ofwater filling the tank to the level of an overflow conduit 210 fromwhich freshwater flows to a reservoir 211 and may be distributed througha suitable outlet indicated diagrammatically by the arrow 212. Water isrecirculated through the pump shroud 203 from an inlet 213 under controlof a valve 214 connected by operating rods 215 and 216 to a hand wheel217 on the deck of the vessel. The vapor intake of the pump 202 which isindicated at 218 is connected through a suction line 220 and aninverted-U 221 to an inverted dome or bell 222 mounted on the vessel andhaving an open end 223 a substantial distance below the level of thesea. The side walls of the bell 222 are insulated as indicated at 224 inorder to prevent undue cooling by the sea water or air surrounding thevalve. A vertical wall 225 is mounted above the casing of the motor 205and extends upward parallel to the wall of the tank 201 and in spacedrelationship thereto to form a vertical chamber 226. The wall 225 isheat-insulated as indicated.

A multiplicity of parallel tubes 227 extend through the tank 201 and areopen at both ends. These tubes slope upwardly as shown and, because ofthe heating of the sea water within the tubes by heat exchange with thehot water within the tank produced by operation of the pump 202, the seawater rises and enters the area 226 and flows upwardly and over theupper end of the Wall 225 onto a SlOping wall 228 which is hinged to thetop of the wall 225 at 230. The slope of the wall 228 is arranged to beadjusted by operation of a suitable mechanism such as a hydraulicactuator indicated at 231. Under some conditions of operation the flowof sea water through the tubes 227 may be produced by movement of thevessel 200 through the water or by anchoring the vessel in a movingstream.

It will now be apparent that during the operation of the pump lowpressure is maintained within the bell 222 which constitutes theevaporating chamber of the system and the heated water will vaporize,the vapor being drawn into the pump and condensed. The tube 221 isthermally insulated and is made sufficiently high to prevent the drawingof liquid through the tube, the height of this loop being of the orderof thirty-five feet for this purpose. The water within the bell 22 iscooled on being vaporized and flows toward the left-hand side as viewedin FIG. 6 and thence downwardly, the circulating being facilitatedfurther by operation of a propeller 232 driven by a suitable motor 233.The slope of the wall 228 may be controlled automatically by a motordevice 234 arranged to actuate the hydraulic operator 231 when thetemperature within the left end of the bell as sensed by a sensingelement 235 falls below a predetermined value. The slope of the wall 228is decreased when the temperature falls so that the heated water mayaccumulate more readily in the upper portion of the bell.

During the operation of the system as illustrated, the propeller 232 hasbeen provided in orderto effect a positive flow of the water within thebell downwardly and out the bottom thereof. It will be understood,however, that there is a natural thermal flow due to the rising eifectof the heated water within the chamber 226 and its movement over anddown along the wall 228 as it is copled and thence downwardly and outthe bottom of the be 1.

During the operation of the system as illustrated the sea water is drawncontinuously through the tubes 227 and a portion of it is vaporizedwithin the bell; the remainder is then returned to the sea. Thisprovides an automatic arrangement for disposing of the concentratedsolution produced by operation of the system and continuous operationand production of large amounts of fresh or distilled water iseifectively accomplished by the system.

All of the systems as described above employ the cylindrical shroud andhelical rotor of applicants invention. As has been mentioned above, theeffect of this rotor may be varied by changing the portion of the rotorwhich is within the shroud, and greater cooling is accomplished byhaving a smaller portion of the rotor within the shroud so that thecooling effect of vapor drawn through the pump and expanded may beutilized and so that there is a minimum heating due to the compressionor vortex forming characteristics of the helical rotor within theshroud. The adjustment of the valve for controlling the recirculation ofWater through the pump has been found to be critical, as mentionedabove, and for this reason the adjustment is made in accordance with theparticular conditions of operation for each application and condition ofoperation at the time. Furthermore, the spacing between the helicalrotor and the shroud is also selected to secure optimum conditions forany one application of the invention.

To further facilitate an understanding of the invention and by way ofexample and not by way of limitation, one

pump embodying the invention was constructed which had the followngdimensions:

Inches Internal diameter of shroud 16 25 Length of shroud 16 27 /2Diameter of shaft 18 (for length of rotor and through chamber 24) 3Distance from bottom of tank to shroud 17 /2 Diameter of rotor helix 24Pitch of rotor helix (2 turns), each turn 5 Length of chamber 24 betweenwall and first rotor turn 12% Diameter of gas inlet 23 10 Diameter ofliquid inlet 21 12 Gate valve 20 12 The pump was mounted in a tank fourfeet five inches wide, six feet ten inches long and nine feet highfilled with water to a height of seven feet and thus containingopproximately 1300 gallons. The rotor was driven by a diesel engine atapproximately 800 rpm. When the gas inlet supply conduit was closed thepump maintained a vacuum of 24 inches of mercury and the temperature ofthe water was observed to rise from 48 F. to 86 F. in eighteen minutes.

While the invention has been described in connection with specificconstructions of the pumping unit and systems, various otherapplications and modifications will occur to those skilled in the art.Therefore it is not desired that the invention be limited to thespecific constructions illustrated and described and it is intended bythe appended claims to cover all modifications which fall within thespirit and scope of the invention.

I claim:

1. A liquid evaporation system comprising means providing an evaporatingchamber, a tank for containing a body of liquid substantially free ofimpurities means including a combined liquid and vapor pump arranged insaid tank and having a liquid inlet and a vapor inlet for circulatingliquid in said tank and for withdrawing and condensing vapor from saidchamber, means for driving said pump, flow control means for adjustingthe flow of liquid through said pump, means for removing liquid fromsaid tank, means for supplying liquid for evaporation to said chamber,means utilizing heat resulting from the operation of said pump forheating the liquid in said chamber, and means for removing concentratefrom said chamber.

2. A liquid evaporation system as set forth in claim 1 wherein said pumpcomprises a substantially cylindrical casing closed at one end and openat its other end, in communication with said tank and a helical rotormounted in said casing for rotation on an axis lying longitudinally ofsaid casing, the periphery of said rotor being spaced from the innerwall of said casing and said rotor being spaced from the closed end ofsaid casing to provide an intake zone, said chamber being connected incommunication with said zone through said vapor inlet to conduct vaporthereto and said flow control means admitting liquid from said tank tosaid zone through said liquid inlet.

3. A liquid evaporation system as set forth in claim 2 including meansproviding thermal insulation for the walls of said casing about saidrotor, means for utilizing liquid to be evaporated for cooling liquidsubstantially free of impurities and admitting it to said zone to lowerthe temperature of the liquid circulated through said pump.

4. A liquid evaporation system as set forth in claim 1 including a heatexchanger positioned to lie below the surface of the liquid in saidtank, and pump means for circulating liquid from said chamber throughsaid heat ,exchanger and back to said chamber for heating the liquid insaid chamber.

5. A liquid evaporation system as set forth in claim 1 including astorage tank for receiving purified liquid from said first mentionedtank, a heat exchange conduit in said storage tank, and selectivelyoperable means for circulating the liquid to be evaporated to saidchamber directly or alternatively through said heat exchanger.

6. A liquid evaporation system as set forth in claim 5 including meansdependent upon the temperature of the liquid in said closed tank foractuating said selectively operable means.

7. An apparatus for removing salt from sea water or the like comprisinga tank for containing fresh water, means providing an evaporatingchamber, means including a combined liquid and vapor pump arranged insaid tank below the level of water therein and having a liquid inlet anda vapor inlet for circulating water therein and for withdrawing andcondensing water vapor from said chamber, and means including heatexchange conduits passing through said tank for conducting sea watercontinuously into said chamber and for heating such water to facilitatethe evaporation thereof.

8. An apparatus for removing salt from sea water or the like as setforth in claim 7 wherein the lower portion of said tank is arranged tobe submerged and said evaporating chamber comprises an inverted vesselarranged to be submerged whereby heated sea water discharged from saidconduits flows into said chamber and thence out the bottom thereof whilea portion thereof is evaporated in said chamber.

9. An apparatus for removing salt from sea water or I the like as setforth in claim 8 including an adjustable horizontally hinged downwardlyinclined baffle plate in said chamber for directing the downwardmovement of water therethrough.

10. An apparatus for removing salt from sea water or the like as setforth in claim 8 wherein said conduits slope upwardly toward saidchamber whereby flow of sea water into said chamber is facilitated bythe heating thereof in said conduits.

11. An apparatus for removing salt from sea water or the like as setforth in claim 8 wherein said means for withdrawing vapor from saidchamber comprises an upwardly extending inverted-U pipe of sufiicientheight to prevent the lifting of liquid water from said chamber to saidtank.

References Cited by the Examiner UNITED STATES PATENTS 1,470,116 10/1923Gray 88 1,966,938 7/1934 Stone 203-26 2,441,361 5/1948 Kirg'an 202 X2,529,622 11/1950 Michael 203-17 X 2,947,379 8/1960 Aubrey 55883,204,861 9/1965 Brown 230-92 3,206,380 9/1965 Davian 202- 3,214,35210/1965 Wells 202187 NORMAN YUDKOFF, Primary Examiner.

F. E. DRUMMOND, Assistant Examiner.

1. A LIQUID EVAPORATION SYSTEM COMPRISING MEANS PROVIDING AN EVAPORATINGCHAMBER, A TANK FOR CONTINING A BODY OF LIQUID SUBSTANTIALLY FREE OFIMPURITIES MEANS INCLUDING A COMBINED LIQUID AND VAPOR PUMP ARRANGED INSAID TANK AND HAVING A LIQUID INLET AND A VAPOR INLET FOR CITULATINGLIQUID IN SAID TANK AND FOR WITHDRAWING AND CONDENSING VAPOR FROM SAIDCHAMBER, MEANS FOR DRIVING SAID PUMP, FLOW CONTROL MEANS FOR ADJUSTINGTHE FLOW OF LIQUID THROUGH SAID PUMP, MEANS FOR REMOVING LIQUID FROMSAID TANK, MEANS FOR SUPPLYING LIQUID FOR EVAPORATION TO SAID CHAMBER,MEANS UTILIZING HEAT RESULTING FROM THE OPERATION OF SAID PUMP FORHEATING THE LIQUID IN SAID CHAMBER, AND MEANS FOR REMOVING CONCENTRATEFROM SAID CHAMBER.